A current of 1mA (rms) is flowing through a 0.00047microF capacitor.
If the frequency of the applied voltage across the capacitor is 10kHz, calculate the (a) the voltage, (b) true power and (c) the reactive power of the capacitor....

is that the complete data?
to calculate active and reactive power u need the resistance offered to the current. if capacitor is an ideal one power is purely reactive.
z= impedance ,
v= voltage,
i=current,
r=resistance,
Xc= capacitive reactance,
z= sqrt(r^2 + Xc^2 )
V=i*z.
power (apparent) = V.I
power (apparent)^2 = reactive power ^2 + active power^2
(there are other ways to get it as well use impedance triangle and find power factor)
reactive power= VIsin(phi)
active power = VIcos(phi)
active power = I^2.R